ATF - oil for automatic transmission. Characteristics, application, shelf life. Compatibility of ATF oils

Automatic gearboxes do not work on traditional gear oils. They are filled with a special ATF-oil. This liquid is a highly indexed composition on a mineral or synthetic basis. Such fluids for automatic transmissions allow the operation of systems controlling and controlling the gear shift. A torque is also transmitted by this fluid from the engine to the automatic transmission. In addition, ATF-oil lubricates friction parts and cools them.

How to create ATF fluids

The first automatic transmission was created in 1938. This design is called Hydramatic. It was distinguished by a vacuum shift system. This unit was created by the engineers of Pontiac. Even then, the company was part of the automotive concern General Motors. Since in General Motors, before starting any innovative development, they preferred to check it in advance and test it in every possible way, a new automatic transmission was installed on Oldsmobile. Tests were successful. And already in 39 year "Hydromatic" was installed as an option on the car Oldsmobile Custom 8 Cruiser. This option cost $ 57.

The role of General Motors in the creation of the first ATF

By the end of the 40s AKPP had become a familiar part of cars. And it's not surprising that the first ATF-oil for automatic transmission was created exactly by specialists of General Motors. It was the world's first specification for the transmission fluid. It was called Type A. Liquid was created in 1949. Then in GM began to develop gear oils, and later to classify, put forward the most stringent requirements for them. Products that were created in the laboratories of General Motots, due to lack of competition, have become an international standard for working fluids for any type of automatic transmission.

From whale oil to new technologies

In 1957, already successfully existing specification was revised and decided to add one small new application - transmission fluid Type A Suffix A (abbreviated name ATF-TASA). After 10 years, B specification was created (this is ATF Dexron-B). As the main ingredient, due to which the liquid had lubricating properties, a blubber was used - it was fat, which was received from whales. But then the development of technology in the production of automatic boxes led the concern to introduce something new. So, in 1973 the new specification Dexron 2C is being developed. In 1981, it will be replaced by Dexron-2D. After the company collapsed with a flurry of negatives from animal advocates, and after a ban on whaling, the company in 1991 creates an innovative formula Dexron-2E. The difference between this product is that it is created on a synthetic basis. Previously, the lubricant was produced on a mineral basis.

The Birth of Dexron-4

In 1994, the entire world public learned about the new specifications, which set out new requirements for viscosity properties and temperature characteristics. The specification also meant more improved frictional properties. This is Dextron-3F and Dextron-3G. After 8 years, Dextron-3H is released. But the most modern and the most stringent is the ATF Dexron-4. Of course, today there are other specifications from other automotive manufacturers. These are such giants as Ford, Toyota, Huinday and others.

How is ATF different from other transmission oils?

To understand the difference, it is necessary to approach the issue from afar. The cars use oils for the engine, gearboxes, hydraulic amplifiers and ATF-oil. What is the similarity between all these fluids? These oils are based on hydrocarbons, which are obtained by processing fossil fuels. This gives some similarities in characteristics. All of the listed products have lubricating properties, increase the sliding between rubbing surfaces. Also all these fluids have good heat dissipation characteristics. They are similar in consistency. This ends all similarities. This is sometimes the cause of gross mistakes, when a novice motorist pours oil in the automatic transmission for "mechanics", and in GUR - brake fluid.

Basic properties of ATF

ATF-oil is one of the most complex fluids in its composition among all the lubricating mixtures used in a modern car. To such a lubricant, high requirements and standards are required. The oil should have a lubricating effect - due to this reduces friction, and at the same time reduces wear in the elements of the gearbox. In this case, frictional forces in the friction groups should increase. This will reduce slippage of brake bands and other components. Also one of the important properties is heat removal. The oil has high heat conductivity and flow characteristics. In this case, the liquid should not foam during operation. An important point is stability, namely the absence of oxidation processes when heated to high temperatures at the time of contact with oxygen. In addition, the oil must have anti-corrosion properties. This is necessary in order to prevent corrosion on the internal nodes of the mechanism. The fluid for the automatic transmission must be hydrophobic (this is the ability to expel moisture from the surface). In this case, it is necessary that the liquid maintain its flow characteristics and hydraulic characteristics. ATF-grease has stable characteristics and high compression ratio in the widest possible temperature range. Another point is the reduction of penetrating abilities through automatic transmission and the presence of a dye.

Typical characteristics for automatic transmission lubricants

Consider several specifications of ATF oil, specifications and figures. For the Dexron-2 specification, the kinematic viscosity is 37.7 at 40 ° C. At 100 degrees, the same parameter will be 8.1. For Dexron-3, the kinematic viscosity is not at all normalized, as well as for other specifications. The viscosity of the Brooksfield ATF oil for Dexron-2 at a temperature of 20 degrees should be 2000 mPa, at 30-6000 mPa, at 40-50,000 mPa. The same parameter for Dexron-3 will be 10, if the pressure is 1500 mPa. The flash point is not lower than 190 degrees for Dexron-2. For Dexron-3 - this parameter is 179 degrees, but not higher than 185.

Compatibility of ATF oils

Any oil (whether mineral or synthetic), can be mixed without any consequences. Naturally, more modern fluids have improved characteristics and properties. If the modern liquid is added to the ordinary liquid, this will improve the properties of the oil that has been poured. The older the specification, the lower characteristics it will possess. Also, the shelf life of ATF oil is an order of magnitude lower. Experts recommend changing this fluid once every 70 thousand kilometers. It is worth noting that many modern manufacturers do not regulate the replacement of this fluid. It is poured for the entire lifetime. But when the car nurses 200 thousand kilometers in one oil, it's not very good. The fact is that the fluid in the automatic transmission is working. It is she who passes the torque from the engine to the wheels. This oil is constantly in operation, even when the machine is at neutral speed. Over time, it collects output products. This is metal shavings, which clogs the filter and sensors. As a result, the box ceases to function normally. Now to the issue of compatibility. No brand will ever fully disclose all information regarding the composition and properties of the produced liquid. Often manufacturers limit themselves to marketing information and advertising, forcing only to buy a specific product. But often this information is groundless. For transmissions with rigid inclusion of torque converter locks, it is recommended to use liquids with constant frictional characteristics. For automatic transmissions with GTP blocking, products with variable properties should be filled. And, finally, regardless of the automatic transmission model, all parts, bearings, gears and other elements are made from the same materials. This means that different types of ATF are not particularly different from each other.

About the features of application and compatibility

If the oil in the box changes entirely, then it is best to purchase a more expensive product. In this case, it is necessary to take into account the constant or variable frictional characteristics. If the budget is limited, then even universal oil ATF will do. Its application will not affect the quality of the box. If the liquid is added, then experts recommend using the product in a class higher or at least not less than flooded. But if the resource reached 70 thousand kilometers, a complete replacement is necessary. It is advisable to perform additional washing. This operation takes an additional 20 liters of oil. It is worth it, but judging by the reviews, this operation perfectly flushes the shavings. And its presence, as is known, complicates the work of an automatic gearbox.

So, we found out what ATF-oil is for ATP.